/Engine/Source/Runtime/Engine/Classes/Components/BrushComponent.h
Determines the DPG the primitive's primary elements are drawn in. Even if the primitive's elements are drawn in multiple DPGs, a primary DPG is needed for occlusion culling and shadow projection.
The DPG the primitive's primary elements will be drawn in.
virtual ESceneDepthPriorityGroup GetStaticDepthPriorityGroup() const